Nitrogen (N)

Nitrogen is an inert gaseous element that accounts for three-fourths of Earth's atmosphere and is found to a lesser degree in the rocks and minerals that make up Earth's crust. Despite having a limited ability to combine with other elements, nitrogen has many industrial applications—most notably in the manufacture of ammonia—and is essential to organic life. In short, nitrogen is one of the most abundant and important chemical elements in existence.

Historical Background

The discovery of nitrogen in the eighteenth century came as a result of scientists' efforts to better recognize the true nature of gases. At the time, the scientific community was just beginning to arrive at an accurate understanding of what gases were and how they behaved. As part of that effort, many scientists experimented with air in hopes of discerning whether it was a unique element or a compound composed of multiple elements. Eventually, they determined that air was a compound and began to identify the different gaseous elements within it.

One of the first elements to be identified as a distinct component of air was nitrogen. Most sources credit Scottish chemist Daniel Rutherford for initially discovering nitrogen in 1772, but others, including English chemists Henry Cavendish and Joseph Priestley and Swedish chemist Carl Wilhelm Scheele, probably discovered the element around the same time. At first, scientists could not decide what to call nitrogen. French chemist Antoine-Laurent Lavoisier suggested that it should be called azote—which means without life—in recognition of its inertness, but few other scientists agreed. Later, in 1790, Jean Antoine Claude Chaptal, another French chemist, successfully lobbied to name the element nitrogen, after it was found to be part of the chemical makeup of both nitric acid and nitrates. This reasoning proved satisfactory, and the name nitrogen stuck permanently.

Characteristics

Like a number of other gases, nitrogen is colorless, odorless, and tasteless. It is represented on the periodic table by the atomic symbol N and is part of a family of elements that also includes phosphorus, arsenic, antimony, and bismuth. The atomic number of nitrogen is 7, and its atomic weight is 14.01. It melts at -210.0°C and boils at -195.79°C. In its solid state, nitrogen is white and snow-like. It is water soluble to a certain extent. In liquid form, it generally resembles water.

Under mild temperature conditions, nitrogen is notably inactive and does not easily combine with other elements. One of the few elements with which nitrogen will combine under certain circumstances is oxygen. When exposed to electrical energy, these two elements will combine to form nitric oxide. The process is known as nitrogen fixation. The nitrogen fixation process also is carried out by certain types of bacteria found on the root hairs of plants. These bacteria extract nitrogen from air that is absorbed into the ground and convert it into nitrates and other similar compounds. Fixed nitrogen, which no other living things can naturally produce, is used by plants to create important protein molecules that make cellular reproduction and growth possible. Fixed nitrogen also is a component of the nucleotides of the deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) molecules that hold an organism's genetic data. As a result, nitrogen is vital to the survival of all forms of organic life.

Applications

Nitrogen has many practical applications. First and foremost, it is used along with hydrogen to manufacture ammonia. Although nitrogen and hydrogen do not combine easily in nature, German chemist Fritz Haber discovered in 1905 that it was possible to coerce them into combining under very high temperature and pressure conditions. Once combined, nitrogen and hydrogen form ammonia. Ammonia is a cleaning agent and an ingredient in the manufacture of products such as fertilizers, explosives, fireworks, insecticides, and herbicides.

Nitrogen gas has other industrial applications, too. Nitrogen may be used as a protective shield when performing processes such as welding and soldering. In the oil industry, nitrogen is used to bring crude oil to the surface of drilling sites.

In its gaseous state, nitrogen commonly is used to create stable, oxygen-free atmospheres for a variety of purposes. Some light bulbs, for example, contain a nitrogen atmosphere that prevents them from burning out too quickly; a reaction in the filament would occur if they were filled with oxygen instead. Since the inherent inertness of nitrogen prevents such a reaction from happening, nitrogen-filled light bulbs naturally have a longer working life.

A nitrogen atmosphere also is useful for preserving important historical documents. When left unprotected, the paper and ink used in written documents react with oxygen and gradually decay. In a pure nitrogen atmosphere, such reactions cannot occur, and decay is prevented. For this reason, documents such as the Declaration of Independence and the first copies of the US Constitution are held in special nitrogen-filled containers designed to keep them intact as long as possible.

In 2024, nitrogen gas was used by the state of Alabama to execute a prisoner by depriving them of oxygen. It was the first time the gas was used for this purpose in the United States, and the experimental procedure generated considerable controversy. Alabama officials claimed the use of nitrogen would be a humane method of capital punishment, but critics argued it could violate the ban on cruel and unusual punishment.

In its liquid form, nitrogen can freeze almost any other type of material. Most commonly, liquid nitrogen is used to flash freeze foods sold in the freezer sections of supermarkets. When dipped into large containers of liquid nitrogen, such foods are instantly frozen and preserved for later consumption. Sometimes liquid nitrogen is used to keep refrigerated foods cold during transport.

Bibliography

"The Element Nitrogen." JLab Science Education, Thomas Jefferson National Accelerator Facility, education.jlab.org/itselemental/ele007.html. Accessed 28 Feb. 2024.

Messerle, Louis. "Nitrogen." Chemistry: Foundations and Applications. Vol. 3. Ed. J.J. Lagowski. Macmillan Reference USA, 2004, 152–154.

Newton, David E. "Nitrogen." Chemical Elements. Vol. 2. Ed. Kathleen J. Edgar. UXL, 2010, 389–399.

"Nitrogen." Los Alamos National Laboratory, periodic.lanl.gov/7.shtml. Accessed 28 Feb. 2024.

Oladipo, Gloria. "Nitrogen Gas Execution: How It Works and Why It's Controversial." The Guardian, 26 Jan. 2024, www.theguardian.com/us-news/2024/jan/26/what-is-nitrogen-gas-execution-risks. Accessed 28 Feb. 2024.